Crops, including orchard/grove-grown fruit, are typically exposed to numerous perils while being grown which result in reduction of crop quality and unsalable commodities. Such perils include exposure to adverse weather, predators, pathogens, and the like. Various chemical formulations (e.g. sprays, dusts) have been developed to reduce the negative effects of many of these threats and these formulations can function as mechanical and/or chemical barriers. However, each of these formulations is rather limited to helping a relatively narrow subset of the negative effects of these perils; and each of the formulations is often relatively expensive or introduces other unintended consequences such as health hazards to humans or environmental pollution.
Sekutowski et al. (U.S. Pat. No. 5,908,708) developed a protective water resistant coating that was formulated as an aqueous dispersion of particulate matter having a hydrophobic outer surface in a low boiling point organic liquid, such as methanol. The particulate matter of the Sekutowski et al. coating can be any finely divided hydrophobic particulate solids including minerals, such as calcium carbonate, mica, talc, kaolin, bentonites, clays attapulgite, pyrophyllite, wollastonite, silica, feldspar, sand, quartz, chalk, limestone, precipitated calcium carbonate, diatomaceous earth and barytes. One agricultural use of the Sekutowski et al. aqueous dispersions is to provide tree leaves with a water resistant coating by spraying the formulation onto the surface of the leaves. The water resistant coating is thought to reduce plant disease and insect damage. However, one major problem with the Sekutowski et al. formulation is the use of large volumes of organic liquids such as alcohols, ketones and cyclic ethers that are highly flammable and pose other health risks to workers during spray application.
Applications of mechanical-protective formulations which additionally function as pesticides (chemical protectants) in plant crops would be a valuable addition to Integrated Pest Management (IPM) practices providing “soft” suppression of pests without disrupting natural control processes. Desirable formulations would be expected to be non-toxic to mammals and thus safe for applicators and farm workers. Application of the protective formulations by commonly employed horticultural spray operations invariably involves extensive treatment of foliage and fruit or vegetable. It is therefore important to develop new formulations that have protective properties against disease to fruits and vegetables as well as against damage caused by insects that inhabit and attack both foliage and fruit.
In addition to pathogen and insect damage, sunburn has been a problem for apple growers (and other commodities as well) for at least 75 years, but its incidence has increased in recent years with the widespread use of dwarfing rootstocks and high-density plantings. Many apple cultivars (e.g., ‘Fuji,’ ‘Granny Smith,’ ‘Jonagold,’ ‘Gala,’ and ‘Braeburn’) are susceptible to sunburn. Prominent growers have indicated that sunburn may be the most significant cullage or quality problem in the industry. Trees are smaller and fruit are more exposed to solar radiation making fruit more susceptible to sunburn.
In summary, there is a lack of adequate means to economically prevent damage to fruit and vegetable crops. Thus, there is a strong need in agricultural markets for an inexpensive and effective composition that prevents or inhibits disease, repels deleterious insects, protects from sunburn, is long lasting, and is relatively amenable to easy application by growers and commercial applicators.